Chain with elastomeric material

ABSTRACT

A chain of metal links has an elastomeric material covering the links and substantially filling the clearance spaces between the links. The chain may be in either contracted condition, or in extended condition. All links may be covered, or intermediate link or links may be uncovered, and extend at a angle to the chain axis, and/or end links may be uncovered. The chain is prepared by wrapping a metal chain in helical, overlap fashion with a strip of raw butyl rubber, after which it is heated uner pressure to cause the rubber to fill the clearance spaces in the chain, to cover the links and to become cured.

United States Patent 11 1 Vasterling 1451 Dec. 4,1973

[ CHAIN WITH ELASTOMERIC MATERIAL 3,298,173 1/1967 Empson 59/78 [75]Inventor: Paul F. Vasterling, Westminster, FOREIGN PATENTS ORAPPLICATIONS Calif- 539,485 9/1941 Great Britain 59/79 R [7.3] Assignee:Hitco, Irvine, Calif. 1 i June 1971 Primary Examiner-Charles W. LanhamAppl. No.:, 151,326

Assistant Examiner-Gene P. Crosby Attorney-Lavine, Cantor & Reich [57]ABSTRACT A chain of metal links has an elastomeric material covering thelinks and substantially filling the clearance spaces between the links.The chain may be in either contracted condition, or in extendedcondition. All links may be covered, or intermediate link or links maybe uncovered, and extend at a angle to the chain axis, and/or end linksmay be uncovered. The chain is prepared by wrapping a metal chain inhelical, overlap fashion with a strip of raw butyl rubber, after whichit is heated uner pressure to cause the rubber to ill] the clearancespaces in the chain, to cover the links and to become cured.

3 Claims, 5 Drawing Figures PATENIEBDEC 41975 3,775,969

INVENTOR PAUL F. VASTERLING ATTORNEYS l CHAIN WITH ELASTOMERIC MATERIAL.BACKGROUND OF THE INVENTION The present invention relates to a chainhaving a coating and filling of elastomeric materiahusable as either atension device, a traction-augmenting device for wheels, or as a shockabsorber.

Metal chains have long been known and used, for a number of purposes;typically, these chains are comprised of interengaged metal links. Suchchains have been used as hold-down' devices, as tension devices in themannerof cables, and also as traction-augmenting devices when applied tovehicle tires. In addition, it has been known to provide a generallytubular casing over the major portion of a chain, so as to preventabrasion of the chain against the surface of a machine or vehicle withwhich the chain is used, as for locking amotorcycle or bicycle.

The chains previously known were not suitable for use in corrosiveatmospheres, and in rigorous environmental conditions, and were subjectto rusting and wear, thereby decreasing their strength over a period oftime. Where chains have been used as tire chains to augment traction ofvehicles, where the vehicle was driven on dry pavement the chainsquickly wore through, so that it was not possible to use such chains forother than very limited periods of time on dry paveme nt.

Chains used as tie-down devices for tying down automobiles ontransporters received repeated shock forces due to irregularities in theroads or rails, so that chains used for this purpose quickly wore out:for example, it is known that conventional chains used for tyingautomobiles on transporters have become worn out after as little as 300or 400 miles of travel. 7

Further, where small airplanes are tied down on the parking areas of anairport, this has left the airplanes exposed to the elements, inparticular to wind forces. In a number of areas, wind gusts occur whichresult in substantial and sudden lift forces on the aircraft wings,thereby imposing strong shock loads on the tie-down devices. As aresult, the lie-down devices, such as ropes, will break, therebyreleasing the airplane with resulting damage to it.

SUMMARY or THE INVENTION The present invention provides a chain,preferably of metal links which are interengaged, which claim ispartially or fully covered and filled with an elastomeric material, suchas cured butyl rubber. The elastomeric material may be applied to achain in either its con tracted condition or its extended condition.When a chain is in extended condition, a clearance space is providedbetween alternate links and where a chain is in contracted condition,clearance is provided between the bights of adjacent links. The linksare covered or coated to a substantial thickness with the cured butylrubber, which substantially fills the noted clearances. The end link orlinks of either the extended or con tracted condition chains may beuncovered or uncoated, so as to provide for ready connection points, orall of the links may be completely covered or coated, so that connectioncan be effected by a clamping type device. In addition, an intermediatelink or pair of links, or several pairs of links intermediate the lengthof the chain may be left uncovered, these links extending at an angle tothe major axis of the chain; such an uncoveed intermediate link or linksmay be used either as an intermediate attachment point, or when such achain is used asatraction augmenting device, such a link or links mayserve as a stud foradded traction, as in sand.

The chain with elastomeric material may be used in harsh or corrosiveatmospheres, as a traction augmenting-device appliedto automobile tires,and as a shock absorber, and the compressed chain functions as a shockabsorber, due to the fact that the elastomeric materialin the clearancespace between the bights of adjacent links will resiliently compressunder tension forces.

The chain is manufactured by placing it in the desired condition, suchas extended or contracted, helically wrapping it with a strip of rawbutyl rubber which may "be about 0.060 inches in'thickness, the wrappingbeing accomplished with a suitable overlap, after which the thuswrappedchain is placed in a vacuum bag, and then the assemblage is placed in anautoclave, where the butyl rubber is cured; the pressure is pounds persquare inch andthe temperature is preferably 250 F, the time periodbeing 20 minutes.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 discloses a chain in contractedcondition, with an elastomeric strip partially covering the chain.

FIG. 2 is a view of a contracted chain with elastomeric materialcovering all of the chain.

FIG. 2A is a cross sectional view taken on the line 2A 2A of FIG. 2.

FIG. 3 is aview of a chain in extended condition, with a portion of thelinks being shown uncovered.

FIG, 4 is a view of a chain having a pair of intermediate linksuncovered and at an angle to the chain axis.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings,wherein like or corresponding reference numerals are used to designatelike or corresponding parts throughout the several views, there is shownin FIG. 1 a chain generally designated 10 made up of a series ofinterengaged metal links 12,

14, 16, 18-and 20. Preferably each of the links is endless, round incross section, and has a considerable length relative to the diameter ofthe metal stock of which is is formed. Thus, with regard to link 14, byway of example, the length of the link between the interior surfaces ofthe bight portions at either end of the link is significantly greaterthan thecombined diameters of the stock materials of the links 12 and16. There is thereby provided a clearance C between the interior bightportion of the right hand end of link 12, and the interior of the bightportion of the left hand end of the adjacent link 14. Similarly, thereis a clearance C between the interior of the left hand bight portion ofthe link 16 and the interior of the right hand bight portion of the link14. Also, the exterior surfaces of the bight portions of the alternatelinks 12 and 16 are in close proximity. The other links of chain 10 aresimilarly arranged, so that the exteriors of the bight portions ofalternate links 14 and 18 are in close proximity, as are the exteriorsurfaces of bight portions of alternate links 16 and 20.

There is also shown at the right. hand portion of FIG. 2 a strip 25 ofelastomeric material, preferably raw butyl rubber having a thickness of0.060 inches. The

strip 25 is shown helically wrapped on the chain with an overlay, whichis preferably approximately one quarter inch for a one inch wide strip.As will be understood, in practice the chain may be of practically anddesired length, and the strip 25 may be applied either to all of thelinks, thereby entirely covering the chain links or alternatively linksat the ends of the chain may be left uncovered.

Referring now to FIG. 2, there is shown the chain 10 in its completedstate. Chain 10, as above noted, is in contracted condition. All of thelinks of the chain will have been covered by the strip 25 of elastomericmaterial. The thus wrapped chain will have been placed in a suitablevacuum bag, such as Mylar, and the metal chain, the elastomeric stripwrapping and the Mylar bag will have been'placed in an autoclave, wherethe pressure is raised to between 50 and 300 pounds per square inch, 100p.s.i. being preferred, and the temperature is raised to 250 F. A periodof at least minutes is preferred, during which time theraw butyl rubber,or equivalent elastomeric material provided by the strip will havemelted sufficiently to cause it to cover and be in intimate contact withthe outer surfaces of all of the links, to flow into the clearances C,and to become cured. Thus, as shown in FIG. 2A, the link 18 is coveredwith the elastomeric material, as is the adjacent link 20. In addition,the cured elastomeric material, designated 25' is shown substantiallycompletely filling the clearance C between links 18 and 20. It will beunderstood that the individual links are discemable in the chain 10, sothat chain 10 has a surface configuration which is generally irregular,similar to that of an uncovered chain, but somewhat attenuated due tothe cured elastomeric material 25. Otherwise stated, the chain 10 has aconfiguration which is somewhat less irregular than that of an uncoveredchain, although it is not, as clearly shown from FIGS. 2 and 2A,cylindrical in outline.

As shown in FIG. 2, the chain 10 has all of the links thereof entirelycoated or covered by the elastomeric material 25'. With such a chain,the elastomeric material in the various clearances C will compress, in aresilient manner, when tension is applied to the chain 10. Thus chain 10will function as a shock absorbing device, and will not readily wear outwhen used as a tiedown for automobiles on an automobile transporter, orin other situations where repeated shock loads are applied. The chain 10as shown in FIG. 2 may be used as a tie-down where sudden strong loadsare applied, as in connection with gust-induced lift forces on a tieddown airplane. In addition, of course, the chain 10 may be used inabrasive or corrosive environmental conditions, where the material 25'will protect the metal of which the chain links are formed.

While the end links of the chain 10 are shown as being covered, so thatexterior gripping devices will be used to connect the chain 10 toequipment, tie-down points, and the like, it is contemplated that an endlink may be partially covered, or the end link may be uncovered,together with a part of the second link, i.e., the second link beingthat link which is adajcent an end link.

Further, while chain 10 in FIG. 1 has been shown with alternate links inengagement, not all of the alternate links need be in engagement, sothat the extent there is provided, for example, a space between theexterior surfaces of the bights of links 14 and 18, there may beprovided a reduced clearnace between links 14 and 16, and between links16 and 18. In this case, there would be less elastomeric material to becompressed, so that there would be reduction in the shock absorbingfunction of such a chain. Where the chain 10 is provided with all of thealternate links in engagement, electricity may be conducted through thechain, but where a separation is provided between some or all of thealternate links, the conductive path will be discontinuous, andtherefore electricity will not be conducted from one end of the chain tothe other.

As used herein, a chain is in its contracted condition when the axisdefined by the links of the chain is substantially straight or in theform of a regular curve, and the bights of alternate links are in closeproximity, there thereby being provided a clearance between the interiorportions of the bights of adjacent links. As used herein, a chain is inits extended condition when the axis defined by the links of the chainis substantially straight or in the form of a regular curve, and whenthe bights of adjacent links are in engagement, and there is clearancebetween the exterior surfaces of the bights of alternate links. As willbe understood, the stated conditions of the links need not obtain forall the links of the chain, since for some purposes, either some or allof the links may occupy intermediate positions, wherein neitheralternate links nor adjacent links are in engagement or variouscombinations of link arrangements may be provided.

Referring now to FIG. 3, there is shown a chain 30, which is in theextended condition. In the extended or stretched condition, a link 36will have the interior of its right hand bight portion in engagementwith the interior of the right hand link bight portion of adjacent link38. Link 40, which is adjacent to link 38, has the left hand bightportion thereof in engagement with the right hand bight portion of link38. There is thereby provided a clearance C between the exterior surfaceof alternate links 36 and 40. These links are shown uncovered in FIG. 3for purposes of clarity, it being understood that all or substantiallyall of the links of the chain 30 will be covered by cured elastomericmaterial 25, which will have been applied in the manner described abovein connection with chain 10, except for the relative positioning of thelinks which make up the chain. The end link 32 will be seen to haveapproximately one half of its length uncovered and the other half oflink 32 will be covered by the elastomeric material 25, which willextend into the opening in link 32. At its other end, link 48 ispartially covered, and end link 50 is completely uncovered, or free ofelastomeric material 25'.

The chain 30 may have both ends thereof as shown at the left end, orboth ends as shown at the right end in FIG. 3. In addition, the chain 30may have the end links completely covered, in the manner shown in FIG.2. In addition, the chain 10 of FIG. 2 may have the ends thereof exposedas shown at either the left or right end of FIG. 3.

The chain 30 of FIG. 3, as is the chain of FIG. 2, is somewhat stifierthan an uncovered chain, by virtue of the elastomeric material 25'. Likechain 10, chain 30 may be flexed, to the extent that it may be held incoiled condition, so that, for example, both chains 10 and 30 may bereeled or trained over pulleys. Chain 30 could conduct electricity, dueto the engagement of each link with its adjacent links, although asnoted in connection with chain 10, the conductive path may be broken byseparating adjacent links somewhat. The chain 30 is suitablefor use incorrosive atmospheres such as in chemical processing plants, in abrasiveatmospheres and in such harsh environments as marine use, and is alsosuitable for use as a traction-augmenting chain for automobile tires.The irregular outline or surface of the chain 30 will provide tractionin snow, while the material 25will protect the metal links from abrasionand wear when driven on dry pavement, and the material 25' will reducethe noise and shock of driving an'automobile with chains 30 over drypavement.

Referring now to FIG. 4, a chain 60 is provided which is generallysimilar to chain 30, except that intermediate links 62 and 64 extend atangles to the major axis of the chain 60. Preferably, links 62 and 64are not covered with the elastomeric material 25', as are substantiallyall of the other links of chain 60. Thus, the links 62 and 64 mayperform the functions of studs when chain 60 is used as atraction-augmenting device, as, for example, in connection with anautomotive vehicle being driven in sand. In addition, the exposedintermediate link 64, or link pair 62, 64 may be used as an intermediateconnection point for the chain 60, so that connections to the chain 60may be made not only at the ends but at the exemplary intermediate link64.

As will be understood, a plurality of pairs of such links as 62 and 64may be provided. In addition, while two links 62 and 64 have been shownextending at angles to the major axis of the chain 60, as will beunderstood, instead of two such links, only one link need be extended sothat its axis is generally transverse to the axis of the chain 60.

There has been provided a chain having interengaged links, with anelastoineric material substantially covering the links and occupyingclearances between the links. The chain may be in either extended orcontracted condition, so that either alternate links are in engagement,or adjacent links are in engagement, respectively. Alternatively, someor all of the links may be in an intermediate position. The elastomericmaterial serves to provide some stiffness to the chain, while permittingit to be flexed to the extent that the chain may be trained overpulleys, reeled and coiled. The chains herein provided may be eitherelectrically conductive or non-conductive. The chain may have all of thelinks covered, may have one or both ends exposed to a greater or lesserextent, such that either part of an end link or all of an end link, orplural end links may be uncovered. In addition, one or more intermediatelinks may extend at an angle to the major axis of the chain, to therebyenable such link to serve as either intermediate attachment links orwhere the chain is used as a traction device, such links will serve asstuds.

The present invention chain may be used either as a shock absorber, as atie-down device having shock absorbing properties, as a tension device,or as a tractionaugmenting device. In addition, the herein disclosedchain may be utilized as an electrical conductor.

There has also been disclosed herein a method of manufacturing a chain,wherein the chain in any de sired condition may be completely orpartially wrapped in a strip of elastomeric material, with subsequentcur ing in an autoclave.

It will be obvious to those skilled in the art that various changes maybe made without departing from the spirit of the invention and thereforethe invention is not limited to what is shown in the drawings anddescribed in the specification but only as indicated in the appendedclaims.

I claim:

I. A method of making a chain comprising:

a. helically wrapping a chain with at least one strip of raw elastomericmaterial so that substantially all of the exterior surface of said chainis covered, and

b. heating said chain and material under pressure for a time and at atemperature to melt and cure said material.

2. The method of claim 1, said material being butyl rubber.

3. The method of claim 2, said heating step being at approximately 250 Fat apressure of not less than 50 p.s.i. or more than 300 p.s.i. for notless than 20 minutes.

1. A method of making a chain comprising: a. helically wrapping a chain with at least one strip of raw elastomeric material so that substantially all of the exterior surface of said chain is covered, and b. heating said chain and material under pressure for a time and at a temperature to melt and cure said material.
 2. The method of claim 1, said material being butyl rubber.
 3. The method of claim 2, said heating step being at approximately 250* F at a pressure of not less than 50 p.s.i. or more than 300 p.s.i. for not less than 20 minutes. 